Lubricant system for drive and support of concrete mixer drum

ABSTRACT

A lubricant system for the front end drive and support of a truck mounted concrete mixer includes a lubricant chamber enclosing the drive connection between the drive shaft and drum with a seal for escape of excess lubricant positioned between the drum head and a spherical surface on a stationary gear housing. Grease connections with lubricant passages leading from the gear housing to a rear shaft support bearing and from the drum head to a spherical drum support bearing provide lubricant for these bearings which then passes to the lubricant chamber. A drum retaining arrangement on the rear end of the support shaft is lubricated from a spherical support bearing and a lubricant return passage connects to the lubricant chamber.

United States Patent lBuelow et al.

[ Jan. 29, 1974 LUBRICANT SYSTEM FOR DRIVE AND SUPPORT OF CONCRETE MIXERDRUM [73] Assignee: Rexnord Inc., Milwaukee, Wis.

[22] Filed: June 27, 1972 [21] Appl. No.: 266,775

2,563,336 8/1951 Jaeger 259/177 R 3,108,839 10/1963 Johnson 308/187Primary ExaminerManuel A. Antonakas Attorney, Agent, or FirmSughrue,Rothwell, Mion,

Zinn & Macpeak [5 7] ABSTRACT A lubricant system for the front end driveand support of a truck mounted concrete mixer includes a lubricantchamber enclosing the drive connection between the drive shaft and drumwith a seal for escape of excess lubricant positioned between the drumhead and a spherical surface on a stationary gear housing. Greaseconnections with lubricant passages leading from the gear housing to arear shaft support bearing and from the drum head to a spherical drumsupport bearing provide lubricant for these bearings which then passesto the lubricant chamber. A drum retaining arrangement on the rear endof the support shaft is lubricated from a spherical support bearing anda lubricant return passage connects to the lubricant chamher.

7 Claims, 2 Drawing Figures LUBRICANT SYSTEM FOR DRIVE AND SUPPORT OFCONCRETE MIXER DRUM BACKGROUND OF THE INVENTION 1. Field of theInvention This invention relates to improvements in lubricating systemsfor front end drive and support of truck mounted concrete mixer drums.

2. Prior Art It is known in the prior art to support and drive aconcrete mixer drum mounted on a truck with the drum head. inclinedforwardly, driven from the front, and supported on the drive shaft,together with means for allowing misalignment between the drum and driveshaft due to flexibility in the truck mounting the drum. In these priorart arrangements, however, there is no means to positively supplylubricant such as by grease fittings and passages to the main drumsupport, the driving coupling, or the bearing supporting the driveshaft. There is a need for such a lubrication system in the art.

# SUMMARY OF THE INVENTION This invention provides an unique arrangementfor lubricating the drum spherical support bearing, the rearmost driveshaft support bearing, and the drive coupling for a front end driven andsupported mixer drum. Specifically, grease connections in the gearhousing and drum connect through lubricant passages to the rear driveshaft support bearing and the spherical drum support bearingrespectively. These bearings are in turn in fluid communication with thechamber surrounding the drive connection so that lubricant passing fromthe bearings lubricates the drive connection. The drive connectionchamber is sealed by a lip seal carried by the drum and sealing on aspherical surface of the gear housing having its curvature at the centerof load. A drum retainer arrangement between the rear end of the driveshaft and the drum is lubricated from the spherical drum support bearingwith excess lubricant returning through a passage in the drum head tothe lubricant chamber surrounding the drive connection.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevation view of atruck mixer incorporating the lubricant system of this invention for itsdrive and support system.

FIG. 2 is an enlarged detailed sectional elevation view illustrating thelubricant system for the drum drive and support arrangement.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to FIG. 1, atruck carries a concrete mixer drum 112 having its head 14 positionedforwardly of the truck and inclined downwardly as is known in the art.The drum is driven by a gear reduction unit drive assembly 16 containedwithin the gear housing 18.

Referring to FIG. 2, a final drive gear 20 of the gear reduction unit ismounted on the main drive shaft 22 by between the stake nut 36 and thehousing boss 30 and a cover plate 40 is attached by screws to thehousing boss.

An oil seal 42 positioned rearwardly on shaft 22 is between the gearhousing 18 and the drive shaft 22 and defines the rearmost portion ofthe lubrication system of this invention. A tapered roller bearing 44constitutes the rearward support bearing for the drive shaft 22 and ismounted in a housing boss 46 and on shaft surface 48. A grease fitting50 screwed into the housing boss 46 connects into a lubricant passage 52in fluid communication with the rearward bearing 44.

A ring 54 is attached to the gear housing 18 by screws 55 extending intoboss 46 and defines a labyrinth oil seal passage between its groovedsurface 56 and a surface 58 of external drive flange 60.

The external drive flange 60 is attached to the drive shaft 22 by aspline connection 62.

The drum head 14 carries a mounting ring 64 welded thereto which in turnhas studs 66 extending outwardly for the mounting of an internal driveflange 68. Nuts 68 secure the internal drive flange to the drum. Gearteeth 70 and 72 on the internal and external drive flanges 60 and 68respectively constitute the drive connection between the drive shaft 22and the drum 14 and are formed to allow for the normal misalignmentwhich the drum encounters in use.

A main lubrication chamber 74 surrounds the drive connection formed ofinternal and external drive flanges 68 and 60 and is defined on one sideby a drum head hub 76 and on the other side by a seal housing 78. Aflange-type seal 80 is carried by the oil seal housing 78 and retainedtherein by a cover ring 82. Srews ,84 hold the housing 78 to theinternal drive flange 68 and the drum hub 76.

A grease fitting 86 screwed through the oil seal housing 78 and into theinternal drive flange 68 connects with a lubricant passage 90. Thislubricant passage extends through hub 76 and then through a web 92 ofthe hub 76 and leads to the outer portion 94 of a spherical bearing. Alubricant passage 96 in this spherical bearing connects the lubricant tothe bearing surface. An inner spherical bearing portion 98 is mounted onshaft surface 100. The curvature of the spherical bearing surfaces is ona radius from the center of load 102 so that as the drum is misaligneddue to any lirnberness or flexibility of the truck during the drive, theouter spherical bearing portion 94 attached to the drum will moverelative to the inner spherical bearing surface part 98 carried by thedrive shaft 22. A spacer 104 is positioned between the inner sphericalbearing portion 98 and the external drive flange 60.

A retainer means or arrangement 1106 is provided for assisting gravityin retaining the drum onto the part spherical bearing. This retainerarrangement is within a chamber 108 in the drum hub 76 and includes aninner spacer 110, an outer spacer 112, and Belleville washers or spacermembers 1114 between the outer spacer and end plate 116 screwed into theend of shaft 22. The inner spacer ll 10 may radially float and thesurfaces between the two spacers are on a curve with its center ofcurvature at the center of load. A cover plate 1 l8 defines one wall ofchamber 108 and a return lubricant passage 120 is contained in the hub76 connecting chamber 108 with main lubricant chamber 74.

The gear case to the left of oil seal 42 as shown in FIG. 2 is oillubricated whereas the lubricant system of this invention contemplatesgrease lubrication of the rearmost support bearing 44, the main drumspherical support bearing 94, 98 and the drive connection 60, 68.

In operation, lubricant is injected through grease fitting 50 intopassage 52 and passes in the direction of arrow a through the taperedroller bearing 44 due to oil seal 42 blocking its passage to the left asviewed in FIG. 2. The lubricant passes along the path indicated by arrowb through the labyrinth defined between surfaces 56 and 58 and then inthe direction of arrow c into chamber 74. When chamber 74 is filled withlubricant, excess lubricant can pass out under the lip seal 80 hearingagainst spherical surface of ring 54. This spherical surface also hasits center at the center of load 102. This arrangement, including thelabyrinth, maintains adequate lubrication for the bearing 44, insuringthat it does not run dry.

Additional grease is then injected into grease fitting 86 where itpasses into passage 90 as indicated by arrow d. It then passes throughthe radially directed leg of passage 90 as indicated by arrow e intolubricant passage 96 and lubricates the bearing surfaces of the partspherical bearing parts 94 and 98. Lubricant escapes from these bearingsurfaces and passes as indicated by arrow f outwardly into chamber 74.Some of this grease will pass through the mating teeth 70 and 72 of thedrive connection as indicated by arrow 3 and the excess will escapethrough the lip seal 80.

For lubricating the retainer means 106 lubricant escapes from the rearend of spherical bearing 94, 98 as indicated by arrow h and passesbetween the spacers 110 and 112 lubricating the same as they move, itthen passes as indicated by arrow i through passage 120 in hub 76 andthen as indicated by arrow j through the drive arrangement and anyexcess passes out the lip seal 80.

As can be seen by this arrangement of lubricating, both bearings, therearmost support bearing for the main shaft and the spherical supportbearing for the drum are positively lubricated by grease and excessgrease passes into a main lubricant chamber surrounding the driveconnection of the internal and external drive flanges 68 and 60 andexcess grease, indicating that the entire assembly is greased, passesout through lip seal 80 bearing against spherical surface of ring 54.

We claim:

1. A lubricant system for a concrete mixer drum front end drive whichincludes: a drive shaft rotatably supported by forward and rearwardbearings within a gear housing, a mixer drum supported at its head atits forward end on a spherical support bearing surface carried by thedrive shaft, and a drive connection from the drive shaft to the drumhead positioned between the spherical bearing and the rearward supportbearing in the plane of the center of load of the drum, the lubricantsystem comprising: a seal extending between the gear housing and driveshaft between the forward and rearward bearings, a grease fitting andpassage in the gear housing to a space in front of the seal and in fluidcommunication with the rearward bearing, a labyrinth restricting passagefor grease between the rearward bearing and the drive connection,another grease fitting connected to a passage in the head of the drumand in fluid communication with the spherical bearing surface, a chamberenclosing the drive connection defined by the head of the drum and aportion of the reannost surface of the gear housing, and a seal at thejuncture of the chamber between the gear housing and the drum head.

2. A lubricant system as defined in claim 1 wherein the last recitedseal is a lip seal carried by the drum head with its lip in contact withthe spherical surface of the gear housing having its center concentricwith the center of the spherical support bearing.

3. A lubricant system as defined in claim 2 wherein the sphericalsurface of the gear housing is on a separate ring shaped member attachedto the housing.

4. A lubricant system as defined in claim 3 wherein the labyrinthpassage is defined by a portion of the surface on the separate ringshaped member attached to the gear housing.

5. A lubricant system as defined in claim 1 wherein the mixer drumfurther includes retainer means between the rear end of the supportshaft in the drum head for applying a force tending to hold the drumonto the spherical support bearing, and the lubricant system furthercomprises a chamber in the drum head in communication with the sphericalsupport bearing to receive lubricant therefrom, the chamber containingthe retainer means, and a return passage from the drum head chamber tothe chamber enclosing the drive connection.

6. A lubricant system for a concrete mixer drum drive which includes: adrive shaft rotatably supported by first and second bearings within agear housing, a mixer drum supported at its head end on the drive shaft,and a drive connection from the drive shaft to the drum head positionedbetween the end of the drive shaft and the second support bearing, thelubricant system comprising: a seal extending between the gear housingand drive shaft between the first and second bearings, a grease fittingand passage in the gear housing to the space between the seal and secondbearing and in fluid communi-cation with the second bearing, a chamberadjacent the drive connection defined by the head of the drum and aportion of the rearmost surface of the gear housing, and a seal at thejuncture of the chamber between the gear housing and drum head.

7. A lubricant system for a concrete mixer drum drive as in claim 6further comprising a labyrinth restricting passage for grease betweenthe second bearing and the chamber.

1. A lubricant system for a concrete mixer drum front end drive whichincludes: a drive shaft rotatably supported by forward and rearwardbearings within a gear housing, a mixer drum supported at its head atits forward end on a spherical support bearing surface carried by thedrive shaft, and a drive connection from the drive shaft to the drumhead positioned between the spherical bearing and the rearward supportbearing in the plane of the center of load of the drum, the lubricantsystem comprising: a seal extending between the gear housing and driveshaft between the forward and rearward bearings, a grease fitting andpassage in the gear housing to a space in front of the seal and in fluidcommunication with the rearward bearing, a labyrinth restricting passagefor grease between the rearward bearing and the drive connection,another grease fitting connected to a passage in the head of the drumand in fluid communication with the spherical bearing surface, a chamberenclosing the drive connection defined by the head of the drum and aportion of the rearmost surface of the gear housing, and a seal at thejuncture of the chamber between the gear housing and the drum head.
 2. Alubricant system as defined in claim 1 wherein the last recited seal isa lip seal carried by the drum head with its lip in contact with thespherical surface of the gear housing having its center concentric withthe center of the spherical support bearing.
 3. A lubricant system asdefined in claim 2 wherein the spherical surface of the gear housing ison a separate ring shaped member attached to the housing.
 4. A lubricantsystem as defined in claim 3 wherein the labyrinth passage is defined bya portion of the surface on the separate ring shaped member atTached tothe gear housing.
 5. A lubricant system as defined in claim 1 whereinthe mixer drum further includes retainer means between the rear end ofthe support shaft in the drum head for applying a force tending to holdthe drum onto the spherical support bearing, and the lubricant systemfurther comprises a chamber in the drum head in communication with thespherical support bearing to receive lubricant therefrom, the chambercontaining the retainer means, and a return passage from the drum headchamber to the chamber enclosing the drive connection.
 6. A lubricantsystem for a concrete mixer drum drive which includes: a drive shaftrotatably supported by first and second bearings within a gear housing,a mixer drum supported at its head end on the drive shaft, and a driveconnection from the drive shaft to the drum head positioned between theend of the drive shaft and the second support bearing, the lubricantsystem comprising: a seal extending between the gear housing and driveshaft between the first and second bearings, a grease fitting andpassage in the gear housing to the space between the seal and secondbearing and in fluid communi-cation with the second bearing, a chamberadjacent the drive connection defined by the head of the drum and aportion of the rearmost surface of the gear housing, and a seal at thejuncture of the chamber between the gear housing and drum head.
 7. Alubricant system for a concrete mixer drum drive as in claim 6 furthercomprising a labyrinth restricting passage for grease between the secondbearing and the chamber.